Childom Cable Tunnel project accepts TBM

Thailand – Factory acceptance for the Childom Cable Tunnel’s TBM took place in April. The 4.27m-diameter Terratec machine will bore the tunnel for a new high voltage cable tunnel in Bangkok.

Geological conditions along the 1.35km tunnel alignment consist of stiff to very stiff clay with lenses of sand and a groundwater head of about 2 bars. The TBM’s soft ground cutterhead features an open spoke design with the addition of knife bits to assist break-in and break-out of the concrete shaft eyes.

Universal tapered precast concrete segments will typically be installed as the machine progresses, with shorter steel segments utilised during the course of the sharp radius curves.

A spokesperson for the manufacturer said, “Running from the Central Embassy mall and MEA’s Chidlom Electrical Facilities southwards to Lumphini Park, the project is located in one of the busiest and most built up areas of downtown Bangkok, and is subject to tight alignment constraints including the need to carefully navigate the foundations of the Chit Lom BTS Skytrain Station. To achieve this, the TERRATEC Earth Pressure Balance Machine has been designed with an extreme X-type articulation system, which can accommodate very tight radius curves.”

Due to heavy traffic and the physical limitations of this built up area – which includes numerous high-rise buildings and the skytrain viaduct – logistics during the launch and operation of the TBM will be extremely challenging, especially during the transportation and delivery of oversize TBM parts for assembly at site. This has reportedly required extensive advance-planning.